This invention relates to heat pumps, and in particular, to a closed air cycle system for heating and cooling the interior of a structure.
Heat pumps have long been known in the art. While most present day heat pumps use freon, an environmentally unfriendly composition, early theories regarding the heat pump contemplated the use of air in a closed system. In an air cycle heat pump, an electric motor drives an air compressor which in turn is connected to a turbine. Air is taken into the compressor and compressed such that the air increases in temperature and pressure. In order to heat the interior of a structure, the air is passed through a heat exchanger in order to effect a heat exchange between the compressed air and the room to be heated. While the compressed air loses some of its heat in the exchange, the compressed air remains warm and maintains its pressure. The warm air is passed through a turbine such that the air is expanded and hence cooled substantially. The energy generated by the turbine may be used to partially operate the electric motor of the compressor. The cooled expanded air then passes through a heat exchanger so as to effect a heat exchange between the cool air and the outside air so as to partially reheat the expanded air. The expanded air is taken back into the compressor where the cycle is repeated.
In order to cool the interior of a structure, the heated, compressed air is passed through a heat exchanger so as to effect a heat exchange between the compressed air and the outside air. In this manner, a portion of the heat is dissipated. The warm, compressed air is then passed through the turbine where it is expanded and cooled. The cool, expanded air is passed through a second heat exchanger so as to effect a heat exchange between the cool, expanded air and the air within the interior of the structure, thereby cooling the interior.
While the closed air cycle heat pump system is functional, the system is inefficient. During the heating cycle, the compressor takes in the very cool air which has just passed through the second heat exchanger. As a result, the compressor must do considerable work to compress the air to a temperature which can heat the interior of a structure. Similarly, during the cooling cycle, the compressor must do considerable work to compress the very cool air to a sufficient pressure and temperature to effect the heat exchange between the compressed air and the air outside of the structure.
It is therefore a primary object and feature of this invention to provide a closed air cycle system for heating and cooling the interior of a structure which is highly efficient and economical.
It is a further object and feature of this invention to provide a closed air cycle system for heating and cooling the interior of a structure which is environmentally friendly.
It is a still further object and feature of this invention to provide a closed air cycle system for heating and cooling the interior of a structure which is easy to install and cost effective.